The saga over Minnesota's state grain continues at the state Capitol with no obvious solution in sight.

After vetoing a rollback of the state's wild rice sulfate rule on Wednesday, Gov. Mark Dayton said he would put together a group of stakeholders to work on a solution to the dispute "for as many hours as it takes," before the Legislature adjourns on May 21.

For him, that solution must not go against current federal law and should provide "a better way of achieving what we all want, which is water quality and wild rice protection and jobs," he said during an appearance in Rochester.

The bill lawmakers sent to Dayton would nullify the state's current sulfate discharge limit of 10 milligrams per liter in waters where wild rice grows. Given that the rule has rarely — if ever — been enforced, the group of GOP and some DFL lawmakers say it makes no sense to keep it in place, especially when city wastewater systems, taconite mines and other industries face millions of dollars in upgrades if it were to be enforced.

"We've got a plethora of science, but it continues to evolve and it's going to lead us to the right answer, but we cannot continue to push and impose a standard from 1973," said Rep. Dale Lueck, R-Aitkin, following the governor's veto.

Lueck said a special treatment system called reverse osmosis can successfully remove sulfate, but "we do not have the money to put those kinds of things in effect."

The story of sulfate limits to protect wild rice is a long one. The rule was adopted in 1973 after a scientist's study showed wild rice did not thrive in waters with high sulfate levels. But without good, affordable methods to remove sulfate from wastewater, the rule proved difficult to enforce.

The U.S. Environmental Protection Agency questioned the lack of enforcement, but the Minnesota Chamber of Commerce sued after the Minnesota Pollution Control Agency in 2010 started moving toward enforcement of the sulfate rule.

Lawmakers then directed the agency to update the rule based on newly conducted science. The agency did so, but an administrative law judge rejected the new rule.

Based on that decision, Lueck and other lawmakers passed legislation to prevent the state from adopting that rejected rule while also nullifying the longstanding rule. The lawmakers agreed to create a wild rice work group and give it $500,000 to come up with a solution.

Dayton has acknowledged the 1973 rule is outdated but has stood by MPCA officials, who argue the state would face lawsuits if it got rid of the rule altogether. Commissioner John Linc Stine has said the science was up-to-date and accurate when the agency came up with the now-rejected rule in 2015 but acknowledged the agency must go back to work on figuring out how to apply it.

Indian tribes and environmentalists who have pressured the agency over the years to enforce the sulfate rule applauded Dayton's veto, especially as they have watched a series of environmental protection rollbacks at the federal level.

"Right now there is such a broad attack on our environment, water quality and the rule of law, and they saw this as one chance when they could weigh in and save something," said Paula Maccabee, advocacy director for Water Legacy, one of several groups that delivered hundreds of postcards to the governor asking him to veto the bill.

Maccabee said she's hopeful lawmakers can come up with a solution that would help mining companies adopt better wastewater treatment technology.

"It is possible to have a win-win situation, where there's an investment in clean, modern technology, there's clean water, and (we) also maintain jobs in the taconite mining industry up north. And I hope we move to that direction," she said.

The bill's proponents also sounded hopeful following the veto.

"Wild rice is a rich part of our Minnesota history, and it's going to continue being part of histories going forward. So it behooves us to get this right," said Rep. Peggy Bennett, R-Albert Lea.